Simple Ruby Pipes | Verbose Logging

Here's something I cooked up this evening. Nothing too epic, but it's a neat illustration of metaprogramming with ruby.

	#!/usr/bin/env ruby

	class Symbol
	def pipe(method)
	proc { \|array\| array.send(method) { \|elem\| elem.send(self) } }
	end

	def detect
	pipe(:detect)
	end

	def select
	pipe(:select)
	end
	alias :filter :select

	def reject
	pipe(:reject)
	end
	end

	class Array
	alias :old_pipe :\|

	def \|(other)
	case other
	when Symbol
	self.map { \|elem\| elem.send(other) }
	when Proc
	other.call(self)
	else
	old_pipe(other)
	end
	end
	end

	a = [' foo ', ' bar ', ' ', ' baz ']

	puts a.inspect # => [" foo ", " bar ", " ", " baz "]
	puts (a \| :strip).inspect # => ["foo", "bar", "", "baz"]
	puts (a \| :strip \| :upcase).inspect # => ["FOO", "BAR", "", "BAZ"]
	puts (a \| :strip \| :upcase \| :empty?.reject).inspect # => ["FOO", "BAR", "BAZ"]
	puts (a \| :strip \| :upcase \| :empty?.select).inspect # => [""]

view raw pipes.rb hosted with ❤ by GitHub

Ruby allows you to reopen classes and add methods to them. You can also make a Module and include that in a class to add methods. I've added four methods to the Symbol class and overridden one method in the Array class (using alias to keep the old method around since super doesn't quite work).

Now we can pipe arrays like bash using a simple syntax! Wee!